Tektronix TDS 684A, TDS 744A, TDS 784A Frequency High

Appendix B: Algorithms
TDS 684A, TDS 744A, & TDS 784A User Manual B–7
2. From this sample, continue the search to find the first (negative) crossing of
. The time of this crossing is . (Use linear interpolation if
necessary.)
3. From , continue the search, looking for a crossing of . Update
 if subsequent  crossings are found. When a  crossing is
found, it becomes . (Use linear interpolation if necessary.)
4.  =  – 
High
HighRef
LowRef
Low
TLFTHF
Fall Time
Figure B–2: Fall Time
Timing measurement. The reciprocal of the period. Measured in Hertz (Hz)
where 1 Hz = 1 cycle per second.
If  = 0 or is otherwise bad, return an error.
 = 1/
100% (highest) voltage reference value. (See High, Low on page B–1.)
Using the min-max measurement technique:
 = 
Frequency
High